As a cartridge type recording medium, the Blue-ray Disc storing an optical disc having a large capacity recording area has been developing in recent years. The shape of the Blue-ray Disc can mainly be divided into two types by the shape of the cartridge. One is a shield type cartridge (refer to, for example, Patent Document 1), and the other is an open type cartridge (refer to, for example, Patent Document 2).
Herein, the shield type cartridge includes a cartridge body, an optical disc rotatably provided inside the cartridge body, an openable and closable shutter which serves as a window for reading or writing the optical disc, and a chucking plate and a plate holder which hold, collaborating with a disc table of the recording medium drive device, the optical disc when the cartridge is housed inside the recording medium drive device. Further, a projected part is projected from the upper surface of the cartridge body in the position where the chucking plate and the plate holder are incorporated.
On the other hand, the open type cartridge includes a cartridge body, an optical disc rotatably provided inside the cartridge body, an openable and closable shutter which serves as a window for reading or writing the optical disc. The open type cartridge does not include a chucking plate and a plate holder, which are included in the shield type cartridge. Accordingly, the recording medium drive device is provided with a clamp mechanism for rotatably holding the optical disc. Further, since a space for setting the chucking plate and the plate holder is unnecessary, the open type cartridge is thinner than the shield type cartridge, which has a projected part formed on the upper surface of the cartridge body, so that there is a difference in shape between the shield type cartridge and the open type cartridge.
[Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-109343 (FIG. 1 and FIG. 2).
[Patent Document 2] Japanese Patent Laid-Open Publication No. 2003-162860 (FIG. 1).